1. Technical Area
The present invention relates generally to the area of medicine, particularly surgery. In surgery, instruments, devices or methods are used for examining the insides of living organisms and/or o for carrying out surgical operations. Surgical instruments include all those medical instruments that are used primarily in surgery. These also include instruments for ligating or otherwise compressing tubelike or vasiform body parts, preferably blood vessels. Surgical instruments of such kind are categorized as gripping or clamping instruments, of which many different kinds already exist, and they are sufficiently known. Gripping or clamping instruments are used for example in heart, chest and vascular surgery. In heart and chest surgery, the operation carried out is usually open, in which access to the heart is gained by opening up the chest. Access is usually gained with a median sternotomy, wherein a longitudinal incision of approximately 25 cm is usually made through the sternum. The longitudinal incision is necessary to open the ribcage. For a thoracotomy, the chest is opened surgically with an intercostal incision, that is to say a small incision in the space between the ribs. The opening created by the sternotomy or thoracotomy is kept free with a rib spreader, an instrument for parting the ribcage and keeping it open. This opening is used by the surgeon to gain access for surgical operations. Operations on organic body parts may then be carried out through the opening created in the ribcage with a wide variety of other surgical instruments. For example, once the patient's heart is exposed various catheters, cannulas and clamps can be inserted in and attached directly to the heart and the large blood vessels. Typically, the aorta is occluded by placing a vascular clamp round the rising aorta to isolate the coronary arteries from the rest of the arterial system. The surgical instruments that are essential for doing this not only reduce the size of the opening, thereby obstructing the surgeon's activity and field of vision, but also render rapid healing less likely because of the size of the opening needed, the tissue damage this causes, and the trauma caused by the surgical operation itself.
2. Background in the Related Art
The present invention relates to such a medical instrument, particularly a surgical instrument, for example a vascular clamp for occluding tubelike, organic, human or animal body parts such as blood vessels, preferably arteries, consisting of two movable shanks that are connected to each other in scissor-like manner, and having a working part, preferably a clamping and gripping mechanism consisting of two gripping elements at the distal end, and having an actuating mechanism, preferably a handle device with two annular handle parts at the proximal end, and includes a locking mechanism close to the annular handle parts and preferably including two ratchets with detent teeth, which locking mechanism may be used to adjust the gripping elements to one of several locked positions.
Medical instruments of such kind, particularly gripping and clamping surgical instruments of various constructions and designs, have proven their usefulness in surgery many times over, and are known from the prior art.
One known example is the Kocher clamp. The Kocher clamp is a trauma clamp and belongs to the class of grasping surgical instruments. A clamp of this kind is most often used when structures must above all be gripped and held securely, and constricted at the same time. For this purpose, the Kocher clamp has serrated jaws, so that the tissue that is being gripped does not slip forwards from between the jaws.
The curved aortic clamp according to the design by Huland and Noldus is also known, this being inserted between the rectum and the Denonvilliers' fascia in preparation for prostatectomies, to prevent injury to the rectum.
The serration on the jaws of this instrument has already been disclosed by its inventor in U.S. Pat. No. 2,668,538. However, the disadvantage of these instruments is that they do not completely prevent tissue damage.
One such surgical clamp, from the wide variety of such instruments, is described in German Patent No. DE 27 47 625 A1. The handle on this clamp was specifically modified, German Patent No. DE 25 21 4878 C2 illustrates that the claws are curved. In this context, the surgical clamp described in German Patent No. DE 2 060 814 A may be considered as representative of the many different clamp types. The disclosed clamp enables clamping to be carried out safely and securely without the use of sharp edges, thus preventing inadvertent injury to sensitive tissue. Each jaw has at least one lengthwise ridge with a row of teeth, and at least one longitudinal groove to accommodate the teeth in the lengthwise ridge on the opposing jaw. The teeth on the ridges of the associated jaw are offset laterally relative to each other, and the ridges on the associated jaws have flanks extending lengthwise that fit closely together in the clamping position, and are shaped to form a pocket extending lengthwise to accommodate tissue, with a middle section having an enlarged cross section and reduced end sections.
The process of disconnecting blood vessels with the surgical instruments described earlier is carried out according to the same principle. The two jaws of the surgical instruments are moved closer to and farther away from each other using annular handles. A latching or locking mechanism, with which the jaws can be set in one of several different positions, is arranged on the scissor-like elements. One ratchet and teeth cooperating therewith are located on each of the scissor-like elements, or toothed racks with detent teeth as a locking mechanism are arranged on the scissor-like elements. Consequently, the distance between the jaws may only be adjusted incrementally. The major disadvantage of such graduated movement is that the vessel is clamped either too tightly or too loosely.
Another embodiment of an aortic clamp is shown in the “HORIZON” product catalogue issued by Cardiomedical GmbH, on the homepage under Cardio Vision on the MIC Accessories page together with an illustration. The aortic clamp described in the product catalogue is also shown in general in German Patent No. DE 696 32 451 T2, FIG. 4.
In order to avoid the disadvantages of the scissor-like clamps designed with annular handles, and those of the ratchet with detent teeth to form a locking mechanism, German Patent No. DE 20 2007 016 057 U1 suggests a stepless adjustment of the gripping elements for a laparoscopic aortic clamp. Aortic clamps with continuous adjustment of the gripping elements or the jaws may also be seen on the homepage of www.eisold-instruments.com, on the “Aortic clamps” tab under Products.
The most closely related art is considered to be the object of US Patent No. 2003/0212435 A1. According to paragraphs 2, 30 and FIG. 6 in the published document, the object disclosed relates to a surgical instrument that may be disassembled and reassembled, consisting of an operating mechanism, a continuously adjustable gripping and clamping vascular clamp having a body element, a working part, an adjustment mechanism, a coupling arrangement and an actuating tool, which is connected in fixed manner to the operating mechanism.
All of the surgical instruments described in the preceding are similar in respect of their size, their scissor-like form, and usually annular handles for operating the jaws, and a typical locking device.
The most recent developments in heart, chest, and vascular surgery, which indicate a trend towards minimally invasive surgery, are reducing the size of the access opening in the chest, particularly for a thoracotomy, in order to minimize tissue damage and operative trauma to the patient, and to help accelerate the healing process. The drawback of small access openings from the surgeon's point of view is that surgical instruments that must be inserted in such an opening significantly reduce the surgeon's operating area and field of vision, which makes it more difficult to perform the operation.
Accordingly, the movement towards minimally invasive surgery can only be realized successfully if the surgical instruments used are adapted to satisfy the new requirements, the smaller access openings. In other words, the current designs of surgical clamps no longer satisfy medical requirements for surgical operations. In order to reduce the patient's stress and minimize the risk of adverse effects, operations are also performed more rapidly. For this, atraumatic instruments are needed, designed in such a way that their handling makes surgical operations considerably easier.
These purposes are satisfied in part by the object disclosed in US Patent No. 2003/0212435 A1. The object relates to a surgical clamp that may be disassembled and reassembled. Because it may be disassembled, it satisfies the requirement for smaller instruments for use in minimally invasive surgery. The disadvantage of this disassemblable surgical clamp, however, is that it does not satisfy the criterion of optimal handling during an operation.
The task of the present invention is therefore to provide a medical instrument of the type described in the introduction, for use in surgery, which has none of the disadvantages and inadequacies of the known devices as described above, and to offer a technical solution for producing a surgical instrument having simple functional geometry that satisfies these more stringent requirements. The surgical instrument should have the same properties as the surgical clamps according to the related art, as well as superior handling, and at the same time provide for a larger, not a smaller, operating and viewing field for the surgeon.
These problems are solved according to the invention by the characterizing features of claim 1. Advantageous embodiments and improvements of the invention are described in the subsequent, dependent claims and the following descriptions.